Warframe is one of the best, if not THE BEST, free-to-play online game out there. Surprisingly, it doesn't seem to get the spotlight it very much deserves. Part of the reason why is due to Warframe's steep learning curve. It features systems on top of systems which you cannot skip since you're essentially handicapping yourself if you do so.
To add to that, there are also numerous warframes to choose from. These are essentially machine space ninjas each with their own unique set of skills. You can treat them like characters, like in a MOBA to make it easier to familiarize yourself. At the moment, there are 39 available warframes (minus the stronger Prime variants) with more on the way.
Some of them are certainly better than others. Moreover, in choosing the most effective warframe, there are three main categories you need to keep in mind: damage per second (DPS), survivability, and crowd control (CC). With that in mind, here are the top tier warframes that excel in at least one category:
10 EXCALIBUR/EXCALIBUR UMBRA
That's right, the easiest beginner warframe and the poster boy of the game. Depending on who you choose in the tutorial, you can get Excalibur for free. If not, then you can get Excalibur Umbra, which is a stronger and more edgy version, also free in a later quest.
On his own, Excalibur is quite formidable and is one of the best DPS warframes because of his Exalted Blade skill. Beyond that, he also has one handy crowd control panic button in the game, which is his second skill, Radial Blind. It stuns enemies for several significant seconds.
What makes Excalibur unstoppable, however, are two mods (modifications): his exclusive Chromatic Blade, and Condition Overload equipped on his Exalted Blade. Both are fairly easy to obtain and can make Excalibur untouchable in Warframe's endgame content.
Sometimes you just want to enjoy your weapons and not overshadow them with your warframe's killing skills. Rhino or his Prime variant (essentially a stronger and flashier version) lets you do just that and not worry about dying. While all of Rhino's skills are useful and have their own specialties, it's his third skill, Iron Skin, that makes him one of the few hard-to-kill warframes.
On his own, he is not really that viable in the toughest missions in Warframe. However, with two mods, namely Ironclad Charge and Iron Shrapnel, he becomes a tank with the highest amount of effective health in Warframe. With those two mods, you basically use Rhino Charge into a large group of enemies then activate Iron Skin immediately after. Depending on how many you hit, with the charge, Iron Skin will give you 10,000 to 300,000 additional armor.
Ivara has permanent invisibility, meaning she is also top tier. She is also a ranger-themed warframe who uses a bow. As such, her ultimate skill, called Artemis Bow, lets her whip out an innate bow that can shoot multiple arrows. This makes Ivara an outstanding DPS warframe because that bow deals insane amounts of damage no matter the enemy's level.
Paired with her permanent invisibility and other crowd control and specialized skills, Ivara can become an unseen and unstoppable force in Warframe. She is an easy choice in solo endless survival modes for that matter.
Aptly called the War Goddess in the Warframe community. Anyone who has ever teamed up with a player using Trinity will know why. She is an infinite source of energy in Warframe, making it incredibly easy for other players to spam their most useful or most damaging abilities. In a sense, Trinity is also a support frame because of such a skill.
However, her specialization does not stop there. Trinity can also link her health to an enemy, making them receive the damage that would have been inflicted on her. Essentially, this also makes Trinity a tank warframe that can survive the strongest attacks.
Inaros is quite possibly the one warframe in this list that is least reliant on his skills. However, this does not make him less awesome. Because if there is one thing Inaros does best or better than other warframes, it's shrugging off attacks like they're just insect bites.
Inaros' ultimate ability can be cast once and forgotten, as it will give him a ton of armor. Of course, Inaros will still take damage to his health, which, while huge, is not invincible. When that happens, you can easily recover Inaros' health in the blink of an eye with his first skill, Dessication. It blinds and stuns enemies with sand and attacking them will restore a large percentage of Inaros' health if they die. Inaros is quite simple and quite immortal.
Nezha is a faster and more active version of Rhino. He also has a similar skill, called Warding Halo which gives him a ton of armor and makes him difficult to kill. On top of that, Nezha's other skills also have great synergy and functionality. His first skill, Firewalker can both stun and damage enemies who step on the trail of fire and also gives Nezha a speed boost.
Meanwhile, his second skill, Blazing Chakram, can give you infinite amounts of healing orbs for when you need to recover health quickly. His ultimate skill, Divine Spears, is just icing on the cake at this point but still serves as a good crowd control ability and incapacitates multiple enemies.
Ever wanted to obliterate your enemies before you even have them in your line-of-sight? That's where Saryn excels at; she's a top DPS frame and is probably the best at dealing damage to every enemy in a 50+ meter radius. What makes her so powerful is her first skill, Spores, which damages enemies, spreads to other enemies, and strips their armor.
Combined with her third skill, Toxic Lash, and her ultimate skill, Miasma, she can erase any enemy on the map as soon as they spawn. However, Saryn is not very good at surviving and is quite fragile, a glass cannon, if you will. Hence, this is where her second skill, Molt, comes into play as it will draw enemy fire and even regenerate her health when modded.
Nova is a warframe fitting of her name. She can kill anything she sees and all her skills are useful on their own. However, what makes Nova truly formidable is her ultimate skill, Molecular Prime. Depending on how you mod the said skill, it will slow enemies down or make them faster and also makes them take double damage, all in a huge radius.
Unlike Saryn, however, Nova is no glass cannon. She has high survivability thanks to her first skill, Null Star. This can give her up to 90 percent damage reduction. So, not only is Nova untouchable, but she can also shrug off any attack that gets through her Molecular Prime field.
One of the recent warframes to receive her own Primed version, Mesa is among the best warframes you can own. Whether you're rocking the regular or Mesa Prime, she is easily the top warframe in terms of DPS. All this is due to her ultimate skill, Peacemaker which kills any enemy unfortunate enough to cross your crosshairs. This is no matter their level.
Beyond that, Mesa also has two additional skills which also puts her in a tank or survival frame category. The first one is her second skill, Shooting Gallery which disables nearby enemies' ranged weapons and momentarily stuns melee enemies. The second is her third skill, Shatter Shield, which reduces any ranged damage Mesa takes. Pair those two with Peacemaker and you become an unkillable killing machine.
Octavia is a jack-of-all-trades warframe and is perhaps the most overpowered in the game right now. She can draw enemy fire and she can also buff damage a lot. However, Octavia usually shines due to her infinite invisibility skill which can be share to the whole team, meaning all four of you in a squad can be invisible thanks to Octavia.
Essentially, Octavia makes other good invisibility warframes like Loki quite irrelevant. After all, she can be permanently invisible and still do insane amounts of damage. That's like cheating in Warframe.